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Finding the Thermocline


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Hello All!!!

I have a Lowrance Elite 5 Gold Fishfinder and GPS. It records temperature - but where in the water column?!?!? Is it surface water temperature.

I don't think it can give me a temperature indication through the column, can it??

If not, can I still use it to figure out where the thermocline is, or am I guessing????

What is the cheapest and easiest way to figure this out??

Thanks!

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Your Lowrance gives you temp at the transducer (Surface temp). In the beginning of the season, the colder off shore water and the warmer inshore water meet and kind of form a verticle thermocline. As you cross this, you should see the temperature reading change on your fish finder. This moves further off shore as the spring moves into early summer. In the summer that thermocline becomes horizontal and generally moves deeper as the surface warms. You can not see this by looking at your temperature reading on the fish finder. If the thermocline layer is significant enough (the difference in density of the warmer and cooler water), then you can often pick this up on the fish finder if you have the sensativity turned up enough. It will kind of look like a line running across the screen. A lot of guys have probe units that send a speed/temp probe down on the downrigger. This sends the speed and temp reading to a display on the boat which lets you find where the temperature break is.

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Yes, thanks.

I don't have downriggers as I use dipsey divers. However, I was thinking of getting a temp probe and putting a 5 oz weight on it to get it down. I supposed if I test for the horizontal thermocline in 150 ft of water, I should get a good idea of where it is sitting.

Anyhow, is it worth it going to this extent, or do you kind of figure out where it is by looking for fish on the screen?

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Cheapest thing and can estimate depth it went or ya could use a line counter reel is the depththerm. It is a mercury thermometer that is closed in a plastic tube that takes a sample of water after a minute or so and can tell you the temp and depth it went to. Not sure where to find one but it works well.

Mark

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I do have a temp probe right now but I fished for almost all of my life without one and I caught just as many fish as the next guy. The thing that Skipper talked about works but the problem is you'd have to drop it so many times to figure out where the temp change is that by the time you figured it out, it would be time to go home. Also, I've noticed since I got my probe that the depth of the temperature break changes as you troll along. Before I spent money on a probe, I'd save up for a used downrigger. Play with the sensativity on your fish finder and you may be able to see the thermocline but if you can't, just fish at the depth where you see fish on the screen and you should do fine.

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Fishhawk makes a device you attach to your line and gives you temp at 5 ft intervals, I think it's called a fishawk TD. It also tells you the max depth your line reaches. Might be a good thing for finding the actual depth of you dipsy divers and will get you into the thermocline.

They are new to the market this year but I'm sure someone on the site has experience with one.

http://www.gloutdoors.com/marineelectronics.aspx $139.99 here.

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Ha Ha....That's what is so great about this site :yes: something new never saw that thing before ...that gadget,,the fish hawk TD is worth a try for that money. One drop and get the thermocline straight down and have it recorded every 5 feet is much better than the old mercury depththerm.... Like Micky Finn said it's a time intensive cave man style thing compaired to this wonderful gadget...glad I came out from under the rock :lol: ...heck one year warranty and 5 year battery life, better than a X4 when the probe gets lost I guess. I don't know about running it on copper and dipsy line that are susceptible to breakage and the big King salmon runs off with it to show all his friends the shiney new bling he just ripped off the hapless fisherman :devil: But it will work for a one time check with a weight or on the rigger ball.

Of course its not as good as the probe style that has continuous reading at the helm, but a more inexpensive alternative. might be worth a try, for me...when I make my first hundred dollars that the gas tank doesn't get :dull:

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I found a submersible thermometer at LeBaron. Need to hook it up to a jig and drop it down. Leave it for 30 secs - 1 min and then bring it back up to test the water. Cost around $10, so not too bad.

I might try it this weekend in 150 ft of water at 2 or 3 depths (50, 70, 90 ft) to get an idea of where the thermocline is.

Will let you know how it works. Watch this space.

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Holy smokes - just checked out that link carpedium.

That is awsome info - does it actually work?? The thermocline is sitting in the yellow band which looks like around 60 - 90 ft of water, depending on how far from shore you are.

Does this make sense??

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MarkB, go to the classified ,there's a Mac Jac temp probe fore $30. I think it goes down to 150fow and its marked in 10ft.increments and you don't have to wait, you push the button and it will give you the temp where you stop the probe. I still use one, I use about a 6oz sinker on it. You don't have to pull it up to get another reading just keep going down. Find the fishes comfort zone that your after and set your lines in it below and above it.I don't think your paying attention to what the other guys are telling you or you may not have spent $10. IF money is tight slow down and build up a stash, witch the board and you will find some good buys on hand cranks or elect. riggers and maybe a down temp. prob. this is not a poor mans hobby, Take your time and pay attention to what your reading and keep learnig good luck . :)

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Thanks WWIV.

I bought the thermometer before I posted this topic. Have been trolling for only 2 weeks and learning as I go.

Will definitely check out the add. Thanks.

It is not really the money. I don't want to screw anyrhing else down on my boat as it is more a ski boat than a fishing boat.

Something that will attach to my rod is perfect.

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